Paul Sahre after a design by Lustig and Connor; photographs, clockwise from top left, NASA; Menahem Kahana/Agence France-Presse - Getty Images: Paul Shre; Rina Castelnuovo; Rahat Dar/European Pressphoto Agency

WORD spread quickly in some conservative Christian circles when Israeli troops captured the Old City of Jerusalem from Arab forces in June 1967. This was it: Jesus was coming.

But Jesus did not return that day, and the world did not end with the culmination of that Arab-Israeli war.

Neither did it end in 1260, when Joachim of Fiore, an influential 12th-century Italian monk calculated it would, nor in February 1420, as predicted by the Taborites of Bohemia, nor in 1988, 40 years after the formation of Israel, nor after the Sept. 11, 2001, terrorist attacks.

But after last week's devastating earthquake in Pakistan, coming as it did after a succession of recent disasters, the apocalyptic speculation, bubbled up again with impressive fervor on many Christian blogs, in some pews and among some evangelical Christian leaders.

Combined with fears of a global pandemic of avian flu, the calamitous flooding that followed Hurricane Katrina and last year's tsunami in Asia, the predictions of the end of the world are to be expected, religious historians said. After all, Christians have been predicting the end of history since the beginning of theirs.

"The doomsday scenarios are fairly cyclical," said Randall Balmer, a professor of American religious history at Barnard College. "The theology they are based on is a very linear view of history. They believe we are now ramping up to the end of time."

While these predictions have been around for thousands of years, the fixation on the so-called end times may be greater than ever on the American religious landscape, said Timothy P. Weber, a church historian and the author of "On the Road to Armageddon: How Evangelicals Became Israel's Best Friend."

Fascination with the end of days is seemingly everywhere, in popular television ministries (like Pat Robertson's), on best-seller lists (the "Left Behind" series) and even on bumper stickers ("In case of rapture, this car will be unmanned").

What could be behind this fascination? Many church leaders and theologians, including evangelicals, give little effort to trying to interpret natural disasters and other events that might portend the end of history. The preoccupation these days stems mainly from the outsized influence of a specific, literalistic approach to biblical prophecy, called dispensationalism, which only came to occupy a dominant place in American evangelicalism relatively recently.

"Dispensationalists have never had the kind of public exposure and the kind of political power that they have now," Mr. Weber said. As a whole, evangelical Christians are united in their belief that Jesus will come back in human form at some point in history. Where they, as well as members of other Christian groups, have differed is precisely how this will occur, depending on how each interprets a single verse in the 20th chapter of the Book of Revelation and its allusion to a 1,000-year reign by Christ.

This difference, in large part, Mr. Weber said, shapes how much they are "players in the end-time game."

Some theologians read the passage and Revelation less literally. Drawing on references elsewhere in the Bible, they say the verse means that Christian influence will grow in the world until it is completely evangelized, leading to a millennial period of universal peace and prosperity. Because they believe Christ will return after the millennium, they are called post-millennialists.

Others, called amillennialists, believe that the millennial age is unfolding now, through the church, but that evil continues to exist and will only be eradicated when Christ returns.

It is those who read the passage most literally - the so-called pre-millennialists - who hold the most pessimistic views. They believe history is irrevocably deteriorating, on its way toward a period of terrible suffering, called the tribulation, which will only be broken when Jesus returns and rules for a thousand years.

Dispensationalism emerged as an offshoot of this last school, owing its spread in large part to the work of a 19th-century British evangelist, John Nelson Darby.

Darby taught that history unfolds in various stages, or dispensations, and introduced several innovations to pre-millennialism, most prominently, the concept of the Rapture - that before the tribulation, true believers will suddenly be whisked away to heaven. This belief is the basis for the popular "Left Behind" series of novels.

Darby also emphasized the role of the nation of Israel in the end of history; the Israelites' return to the promised land, he said, was a requirement of the Second Coming.

Until the mid-19th century, most American Christians were actually post-millennialists. Their fervor for hastening Jesus' return animated many of the era's social movements, like the abolitionist movement. But the Civil War and the succeeding waves of industrialization, urbanization and immigration - and the social problems that came with them - helped cripple post-millenial optimism. Darby, however, won some important converts, including the evangelist, Dwight L. Moody, and his ideas began to catch on. Dispensationalism's tenets were eventually memorialized in the Scofield Reference Bible, which became a best-seller. Even as American Christianity changed over time, with the ascendance of Billy Graham and a new breed of evangelicals, many of dispensationalism's fingerprints remained. And dispensationalism came back to the fore in the 1980's and onward, with the rise of the religious right and the growing television ministries of many dispensationalists, including Jerry Falwell, Jack Van Impe and John Hagee.

Today, only about a third of evangelicals are truly dispensationalists, estimated Richard Cizik, vice president of government affairs for the National Association of Evangelicals, although he said he thought most evangelicals are generally pre-millennial, harboring a more pessimistic outlook on history.

But the dispensationalists remain the most vocal segment, Mr. Cizik said. Aided by books, television and the Internet, they have shaped a fascination in evangelical culture on the end of days, said Craig C. Hill, a professor of New Testament theology at Wesley Theological Seminar in Washington and the author of "In God's Time: the Bible and the Future," about biblical prophecy. Preaching on the end times is an obvious way to draw an audience, Mr. Hill said.

"It's inherently interesting," he said. "If you have a sign out for the sermon, 'Our obligation to the poor,' you won't get anybody. If you have a sign out for, 'The Internet and the Antichrist,' you'll bring them in."

Dispensationalism offers believers a road map to deal with uncertainty in the world at large. "When somebody says there's a pattern here, and let me tell you what the pattern means, this is what gets a lot of people's attention," said Mr. Weber, the church historian. At this point, dispensationalism's tenets have become so popular that many evangelicals who are in denominations or churches that might not necessarily adhere to dispensationalism have, nevertheless, adopted bits and pieces of it.

But the theology has drawn fire from other evangelicals for its narrow reading of the Bible and its tendency to ignore social problems. "It's still considered by many theologians to be somewhat ahistorical and theologically suspect," said Mr. Cizik, who criticized anyone who would interpret the recent calamities as a sign of the end. "History has taught us not to predict," he said. "I think it's sheer speculation for anyone to place a whole lot of stock in any one particular earthquake or pestilence."

Not that that will stop the prognostications.

Copyright 2005 The New York Times Company. Reprinted from The New York Times, Week in Review, of Sunday, October 16, 2005.